Stuck

Me and my boyfriend have been together 3 years and don't get me wrong we've had some amazing times but recently he has what I would called emotionally abusive towards me. I know this may sound so ridiculous but the whole situation has got me in such a state. Being a young girl (18) with exams going on and a mum who is recovering from cancer it's been a stressful time and my partner is not helping. He will make horrible comments about me and digs until I cry and then call me a little girl for crying and then carry on saying horrible abusive things which leads me to cry even more making the situation so much worse. I try not to cry but it is too hard not to. I know everyone is probably sat here screaming leave him but I can't help clings on to hope that the good times will come back and everything will go back to normal. I know it is probably best to leave him but I have no idea how to? Any advice would be welcomed and much appreciated. I'm a scared and stuck and overall feeling down about the whole situation. I'm worried it's only a certain amount of time until he gets physical!